Structural Integrity Assessment of Composites Plates with Embedded PZT Transducers for Structural Health Monitoring.

Active sensing using ultrasonic guided waves (UGW) is widely investigated for monitoring possible damages in composite structures. Recently, a novel diagnosed film based on a circuit-printed technique with piezoelectric lead zirconate titanate (PZT) transducers has been developed. The diagnostic film is a replacement for the traditional cable connection to PZT sensors and has been shown to significantly reduce the weight of the host structure. In this work, the diagnosed films were embedded into composite structures during manufacturing using a novel edge cut-out method during lay-up, which allowed for edge trimming after curing. In this paper, the effect of fatigue loading on the integrity of PZT transducers is initially investigated. The electro-mechanical impedance (EMI) properties at different fatigue loading cycles were used as the diagnostic measure for the performance of the sensors. At the same time, the behaviours of UGW were investigated at different fatigue loading cycles. It was found that the EMI properties and active sensing behaviours remained stable up to 1 million cycles for the force ranges of 0.5~5 kN and 1~10 kN. Next, the effect of embedding the diagnosed film on the mechanical properties of the host composite structure was investigated. Tensile and compressive tests were conducted and the elastic modulus of composite coupons with and without embedded PZT diagnosed films were compared. The elastic modulus of composite coupons with PZT diagnosed films embedded across the entire coupon reduced by as much as 20% for tensile tests and just over 10% for compressive tests compared to the coupons without embedded sensors. These reductions are considered the worst-case scenario, as in real structures the film would only be embedded in a relatively small area of the structure.

Network pharmacology assessment of Qingkailing injection treatment of cholestatic hepatitis.

OBJECTIVE: To investigate the targets and mechanisms of action of Qingkailing injection (，QKL) in the treatment of cholestatic hepatitis. METHODS: A network pharmacology method was implemented using drug and disease databases to target QKL and cholestasis hepatitis, respectively. The functional protein association network STRING database was used to construct a protein-protein interaction network using R language and the Bioconductor toolkit. The org.Hs.eg.db and clusterProfiler packages were used for gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, which explored biological functions and pathways of potential targets. Targets were then visualized using Cytoscape 3.6.0 software. RESULTS: We screened 121 compounds in QKL and identified 112 targets for the treatment of cholestatic hepatitis. QKL played a role in the treatment of cholestatic hepatitis through 305 biology process terms, 15 cellular component and 29 molecular function terms. The mechanism of QKL action was mainly related to tumor necrosis factor, mitogen-activated protein kinase, and PI3K-Akt signaling pathways. CONCLUSION: The treatment of cholestatic hepatitis by QKL involved multiple targets, biological functions, and signaling pathways that are closely associated with the disease.

Active Health Monitoring of Thick Composite Structures by Embedded and Surface-Mounted Piezo Diagnostic Layer.

An effective approach for an embedded piezo diagnostic layer into thick composite material is presented. The effectiveness of the approach is assessed in comparison to the surface-mounted layer. The proposed manufacturing alleviates difficulties associated with trimming edges of composites when embedding wires. The Electro-Mechanical Impedance technique is used to access the integrity of the piezoelectric sensors bonding process. Comparisons of ultrasonic guided waves are made between embedded and surface-mounted diagnostic layers and their penetration through and across the thickness of the composites. Temperature influences with the range from -40 °C up to 80 °C on embedded and surface-mounted guided waves are investigated. An investigation is carried out into the relationship between amplitude and time-of-flight with temperature at different excitation frequencies. The temperature has significant but different effects on amplitude and phase-shift of guided waves for the embedded layer compared to the surface-mounted layer. A Laser Doppler Vibrometer is used to identify the blue tack and impact damage. Both embedded and surface-mounted layers are shown to be an effective means of generating detectable wave scatter from damage.